Corewire design and construction for medical devices

ABSTRACT

A guidewire for use in ear, nose and throat procedures may include an elongate core wire having a proximal region and a distal region. The distal region of the core wire may include a flattened portion adapted to provide preferential flexure along at least one axis of the wire. The distal region of the core wire may include a tip portion distal of the flattened portion, where at least one cross-sectional dimension of the tip portion is greater than at least one cross-sectional dimension of the flattened portion. The guidewire may include an outer coil disposed around at least a portion of the elongate core wire. The guidewire may also include an atraumatic tip coupled to the core wire or the outer coil.

BACKGROUND OF THE INVENTION

Embodiments of the present invention relate generally to medical devicesand methods and more particularly to minimally invasive devices, systemsand methods for treating sinusitis and other ear, nose & throatdisorders

The human head includes a number of hollow cavities called paranasalsinuses, which connect to the nasal cavity via small openings called“ostia” (sinugular “ostium”). Generally, the human head includes eightparanasal sinuses (two sets of four on each side), called the frontal,ethmoid, sphenoid and maxillary sinuses. The frontal sinuses are locatedin the forehead, the maxillary sinuses are in the cheeks, the ethmoidsare under the eyes, and the sphenoid sinuses are farther back in thehead, near the pituitary gland. Paranasal sinuses are lined withmucous-producing epithelial tissue and have cilia to sweep mucous out ofthe sinuses and through the ostia into the nasal cavity.

Sinusitis is defined as an inflammation of the paranasal sinus liningcommonly caused by bacterial, viral and/or microbial infections, as wellas structural issues such as blockage of the sinus ostia. Symptomsinclude nasal congestion, facial discomfort, nasal discharge, headache,and fatigue. Sinusitis is considered acute when symptoms last 4 weeks orless. The disease is considered chronic when it lasts 3 months orlonger. Sinusitis affects 37 million people each year, making it one ofthe most common health problems in the U.S. It is more prevalent thanarthritis and hypertension and has a greater impact on quality of lifethan diabetes or congestive heart failure. Sinusitis is also responsiblefor $8 billion in direct healthcare expenditures and a significant lossof workplace productivity.

The initial therapy typically attempted when treating chronic sinusitisis drug therapy involving anti-inflammatory agents to reduce theinflammation and antibiotics to treat the infection. A large number ofpatients, however, do not respond to drug therapy and seek a surgicaloption. The most common surgical procedure currently performed forchronic sinusitis treatment is Functional Endoscopic Sinus Surgery(FESS).

In FESS, an endoscope is inserted into the nose and, under visualizationthrough the endoscope, the surgeon removes diseased or hypertrophic boneand soft tissue in the nasal cavity and enlarges the ostia of theeffected sinuses to restore normal drainage of the sinuses. Instrumentsused in FESS procedures are generally rigid surgical shavers, drills andburrs, and not only are the ostia enlarged during FESS procedures, butalso anatomical structures are often removed just to gain access to theostia with the rigid surgical tools. This removal of structuresincreases the post-surgical pain and bleeding after FESS. FESSprocedures are typically performed with the patient under generalanesthesia and involve days or even weeks of recovery, with painful anduncomfortable post-surgical packing of the nasal cavity, bleeding andscarring requiring follow-up debridement procedures.

Due to the invasiveness of FESS procedures, many otolaryngologistsconsider FESS an option only for patients who suffer from severe sinusdisease (e.g., those showing significant abnormalities under CT scan),and many patients who would benefit from a surgical solution to theirchronic sinusitis nevertheless avoid surgery. Thus, patients with lesssevere disease may not be considered candidates for FESS and may be leftwith no option but drug therapy.

An alternative to FESS employs dilating balloons and related devices forless invasive sinus intervention. Examples of dilating balloons andrelated devices and their methods of use can be found, for example, inU.S. patent application Ser. No. 10/829,917 (Attorney Docket No.ACLRT-003A), entitled “Devices, Systems and Methods for Treatment ofNasal and Sinus Disorders of the Ears, Nose and/or Throat” and filed onApr. 21, 2004; Ser. No. 10/944,270 (Attorney Docket No. ACLRT-022B),entitled “Apparatus and Methods for Dilating and Modifying Ostia forParanasal Sinuses and Other Intranasal or Paranasal Structures” andfiled on Sep. 17, 2004; Ser. No. 11/037,548 (Attorney Docket No.ACLRT-021B), entitled “Systems and Methods for Treating Disorders of theEar, Nose and Throat” and filed on Jan. 18, 2005; and Ser. No.11/150,847 (Attorney Docket No. ACLRT-038B), entitled “Devices, Systemsand Methods Useable for Treating Sinusitis” and filed: Jun. 10, 2005,which are incorporated by reference in their entirety. Less invasiveprocedures of the type described in the above applications may sometimesbe referred to as “Balloon Sinuplasty™” or more generally “Sinuplasty.”

In addition to Balloon Sinuplasty™ devices, systems and methods, theassignee of the present invention has invented other devices, systemsand methods for minimally invasive sinus procedures. For example, anirrigation catheter for use in the paranasal sinuses is described inU.S. patent application Ser. No. 12/011,100 (Attorney Docket No.ACCL-007), entitled “Methods, Devices and Systems for Treatment and/orDiagnosis of Disorders of the Ear, Nose and Throat,” and filed on Jan.23, 2008, the full disclosure of which is hereby incorporated byreference. Another example is a lighted guidewire device for use in aBalloon Sinuplasty™ procedure, such as the embodiments described in U.S.patent application Ser. No. 11/522,497 (Attorney Docket No. ACCL-001),entitled “Methods and Devices for Facilitating Visualization in aSurgical Environment,” and filed Sep. 15, 2006, the full disclosure ofwhich is hereby incorporated by reference.

In some Balloon Sinuplasty™ procedures, as well as in other proceduresinvented by the assignee of the present invention, such as paranasalsinus irrigation using an irrigation catheter device as described in theabove-referenced patent application, a guidewire may be used foradvancement and positioning of one or more devices in or through aparanasal sinus ostium and sometimes into a paranasal sinus itself. Forexample, in some procedures a guidewire may be advanced through anangled guide catheter, through a paranasal sinus ostium, and into aparanasal sinus. A balloon catheter may then be advanced over theguidewire to position a balloon of the catheter in the paranasal sinusostium, and the balloon may then be inflated to expand the ostium. Insome cases, the balloon catheter and guidewire may then be removed fromthe paranasal sinus by pulling them back through the angled guidecatheter. Optionally, the same guide catheter, guidewire and ballooncatheter may be used to access and expand multiple paranasal sinus ostiain one patient.

Although the assignee of the present invention has previously developedguidewires for use in such procedures, improvements are continuallybeing sought. For example, when a distal end of a guidewire is passedinto a sinus, it is often advantageous to continue to pass an additionallength of guidewire into the sinus, thus causing it to curl and turn upon itself and thus facilitating confirmation of the location of theguidewire distal end in the sinus, using fluoroscopy. The distal end ofthe guidewire is also passed in and out of an angled guide catheter atleast once and often more than once. These two parts of the proceduremay often cause the guidewire to kink or bend, and this kinking orbending may make it very difficult or impossible to access subsequentparanasal sinuses in the same patient with the same guidewire. Ideally,the guidewire distal portion should be flexible enough to pass throughtortuous anatomy without damaging the anatomy while also resistant tokinking and bending. The ideal guidewire should also be pushable, toallow it to be advanced through a guide catheter. Such a guidewireshould also be sufficiently strong to support a balloon catheter,irrigation catheter or other device that is passed over it.

The challenges faced by a guidewire for paranasal sinus procedures arealso much more daunting than those faced by a guidewire used incardiology vascular applications. For example, the anatomy in the nasalcavity and paranasal sinuses is composed of bone covered in soft tissue,formed into many folds, twists and turns, so the sinus guidewire facesboth hard tissue that it must navigate and soft tissue that it ideallywill leave relatively undamaged. The circumference and shape of theparanasal sinus cavities vary significantly from patient to patient andwithin a patient. The circumference of a sinus cavity may vary fromabout 0.5 cm to about 10 cm within a patient. Based on the size of thesinus cavity, the amount of guidewire that is positioned in the sinusalso can vary significantly. The amount of guidewire that is positionedin the sinus can also vary based on physician preference as well assupport needed during passage of devices. The guidewire must also passin and out of an angled guide catheter that is usually at leastpartially rigid while still retaining approximately it overall shape.Further, the guidewire must provide support for the balloon catheter,irrigation catheter or other device being advanced over it.

Thus, there is a need for devices and methods for easily navigating thecomplex anatomy of the nasal cavities and paranasal sinuses and fortreating disorders of the paranasal sinuses with minimal complicationsdue to individual variations in anatomy and causing minimal trauma to ordisruption of anatomical structures that are not pathogenic.Specifically, there is a need for a guidewire that balances flexibilityand ease of use with the resilience and rigidity to provide support fora balloon catheter, irrigation catheter and/or other device(s).

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention are related to a guidewire for usein ear, nose and throat procedures. The guidewire may include anelongate core wire having a proximal region and a distal region. Thedistal region of the core wire may include a flattened portion adaptedto provide preferential flexure along at least one axis of the wire. Thedistal region of the core wire may include a tip portion distal of theflattened portion, where at least one cross-sectional dimension of thetip portion is greater than at least one cross-sectional dimension ofthe flattened portion. The guidewire may include an outer coil disposedaround at least a portion of the elongate core wire. The guidewire mayalso include an atraumatic tip coupled to the core wire or the outercoil.

Some embodiments of the present invention are related to a core wire fora device useable in ear, nose and throat procedures. The core wire mayinclude a proximal portion having a first cross-sectional area and adistal tip having a second cross-sectional area. The core wire mayinclude a transitional portion between the proximal portion and thedistal tip. The transitional portion may include a third cross-sectionalarea, where the second cross-sectional area is greater than the thirdcross-sectional area.

Some embodiments of the present invention are related to a method ofmaking a guidewire for use in ear, nose and throat procedures. Invarious embodiments, for example, a method for making a guidewire mayinclude: fabricating an elongate core wire having a proximal section anda distal section; configuring a portion of the distal section to havepreferential flexibility along at least one axis of the portion;configuring a distal tip portion having at least one cross sectionaldimension greater than at least one cross sectional dimension of thepreferentially flexible portion; and disposing an outer coil around atleast part of a length of the core wire.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIGS. 1A through 1D are partial sectional views through a human headshowing various steps of a method for treating a paranasal sinus using aguidewire and a balloon catheter device.

FIGS. 2A through 2F are partial sectional views through a human headshowing various steps of a method for accessing and treating an ethmoidsinus through a natural or artificially created opening of the ethmoidsinus, using a guidewire and a balloon catheter device.

FIGS. 3A through 3C are partial sectional views through a human headshowing various steps of a method of accessing a paranasal sinus using aguide catheter and a guidewire.

FIG. 4A illustrates a cross-sectional view of a guidewire according toone embodiment of the present invention.

FIG. 4B illustrates a close-up view of a distal region of the guidewireof FIG. 4A.

FIGS. 5A and 5B illustrate two views of a core wire according to oneembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention are useful in sinusplastyprocedures, and may also be useful in other less or minimally invasiveprocedures in the ear, nose, or throat. In some sinusplasty procedures,a guidewire is used to probe openings to critical structures andparanasal sinuses. After a distal end of a guidewire has been advancedinto a paranasal sinus, it may sometimes be advantageous to continueadvancing the guidewire, thus causing it to curl up in the sinus. Acurled-up distal portion of a guidewire may facilitate, for example,viewing the distal portion via fluoroscopy, thus allowing a surgeon toconfirm that the distal portion is located in the desired paranasalsinus.

A distal portion of a sinuplasty guidewire may be atraumatic andflexible (to curl and potentially straighten out upon removal), whilealso being at least somewhat stiff (to provide support for passingdiagnostic and therapeutic devices). The distal guidewire portion mayalso enable or facilitate passing devices for therapeutic and diagnosticprocedures by anchoring the guidewire to some degree. The distal portionof the guidewire can be low profile and small to allow easier access andcrossing of narrow ostia and passageways. In certain embodiments, thedistal portion of the guidewire may be resilient enough to keep itsshape after multiple passes through the guide. The preferred guidewiredesign provides the right balance of flexibility and stiffness in thedistal section to support passage of balloon catheters.

Referring to FIGS. 1A-1D, in one embodiment of a Balloon Sinuplasty™procedure, a balloon catheter is delivered over a guidewire to access,cross and dilate a sinus ostium. As shown in FIG. 1A, a guidewire 110may be introduced into a nasal cavity. (A frontal sinus FS, sphenoidsinus, sphenoid sinus ostium SSO, and nasopharynx NP are labeled inFIGS. 1A-1D.) To facilitate navigation through tortuous nasal cavityanatomy, guidewire 110 may have any of a number of configurations. Forexample, in one embodiment, guidewire 110 may be substantially straight,while in alternative embodiments it may angled, curved or bent at aregion between a proximal portion and a distal portion of guidewire 110.In many embodiments, some of which are described in the patentapplications incorporated above by reference, guidewire 110 may beadvanced into the nasal cavity and into a paranasal sinus through aguide catheter (not shown in FIGS. 1A-1D).

In FIG. 1B, guidewire 110 is advanced through the nasal anatomy so thatthe distal tip of guidewire enters a sphenoid sinus SS through an ostiumSSO. In FIG. 1C, a working device in the form of a balloon catheter 120is advanced along guidewire 110 into the sphenoid sinus SS. Typically,balloon catheter 120 will have a guidewire lumen extending through orformed in or on at least a portion of balloon catheter 120 to facilitateadvancement of balloon catheter 120 over guidewire 110. The position ofballoon catheter 120 is adjusted so that the balloon of the ballooncatheter is located in the ostium SSO. In FIG. 1D, balloon catheter 120is used to dilate the ostium SSO. After completion of the procedure,guidewire 110 and balloon catheter 120 are withdrawn from the nasalanatomy.

Another sinus procedure is depicted in FIGS. 2A through 2F, which arepartial sectional views through a human head showing various steps of amethod for accessing and treating an ethmoid sinus ES and ethmoid aircells EAC through a natural or artificially created opening of theethmoid sinus.

In FIG. 2A, an introducing device in the form of a guide catheter 210 isintroduced in an ethmoid sinus ES. Ethmoid sinus ES comprises multipleethmoid air cells EAC. In FIG. 2B, a guidewire 220 is introduced throughguide catheter 210 into a first EAC. Thereafter, in FIG. 2C, a ballooncatheter 230 is introduced over guidewire 220 into the first EAC. InFIG. 2D, balloon catheter 230 is inflated to dilate the structures ofES. In FIG. 2E, guide catheter 210, guidewire 220 and balloon catheter230 are withdrawn leaving a first new passage in the ES. The newlycreated passage in the ES facilitates drainage of the mucous through theES.

Alternatively, in FIG. 2F, only balloon catheter 230 is withdrawn. Theposition of guide catheter 210 is adjusted and guidewire 220 isintroduced into a second EAC. A second new passage from the ES to thesecond EAC further facilitates drainage of the mucous through the ES.This method of dilating the structures of ES can be repeated to createmultiple new passages in the ES.

FIGS. 3A through 3C are partial sectional views through a human headshowing various steps of a method of accessing a paranasal sinus using aguide catheter and a guidewire. In FIG. 3A, an angled guide catheter 390is inserted through a nostril and placed to access a maxillary sinus MS.In FIG. 3B, guidewire 300 is advanced through guide catheter 390, aroundthe angled bend of guide catheter 390, and into the MS. Guidewire 300can be coiled to facilitate identification of guidewire 300 viafluoroscopy and thus verify the location of the distal portion ofguidewire 300 in the MS. As shown in FIG. 3C, guide catheter 390 waythen be withdrawn over guidewire 300, thus leaving guidewire 300 inplace, with its distal end in the MS and its proximal end outside thepatient. Any of a number of working devices, such as a balloon catheter,irrigation catheter and/or the like, can be advanced over guidewire 300into the MS. In such a procedure, it would be advantageous for guidewire300 to have a flexibility and stiffness profile to allow it to slidethrough angled guide catheter 390 and have guide catheter 390 be removedover it, multiple times, without “taking a shape” or retaining a bend orkink. It would also be advantageous for guidewire 300 to have sufficientstiffness support advancement of a balloon catheter, irrigation catheterand/or other device over it.

The foregoing three illustrated examples demonstrate some of thecharacteristics and properties useful for a sinuplasty guidewire,including, but not limited to:

having an atraumatic tip to allow probing of bony structures, cavitiesand openings;

having rigidity to access and cross a narrowed ostium or passageway andto provide support for a balloon catheter or other working device;

having flexibility and a low profile to navigate tortuous anatomy;

being steerable to allow selectively access to the desired anatomy;

having resilience to retain its shape after multiple passes through aguiding member, multiple passes through ostia, multiple curlings insinus cavities, and multiple balloon dilations and removals;

being lubricious to allow ease of passage of working devices; and

having an appropriate length to allow easier handling, improvedperformance, and exchange of devices.

Optimizing for one of the above properties can result in deficiencies inanother property. For example, if the guidewire is too flexible, then itmay become difficult to cross a tight ostium with a balloon catheteradvanced over the guidewire. If the guidewire is too stiff, then it maynot be easy to curl in the sinus. Also, depending on the amount of wirethat curls in the sinus, the balloon support performance of theguidewire may change significantly. A useful total length of theguidewire provides ease of use and improved performance, includingsteerability, handling, and catheter support.

Certain other features may also be advantageous in some guidewireembodiments. For example, the proximal portion of the guidewire may besufficiently stiff to allow translation of torque from the proximalregion to the distal region, but sufficiently flexible to allow theremoval of maxillary and frontal guides (which are typically more rigidthan a guidewire) without losing the guidewire shape. Further, thedistal portion of the guidewire that comes out of the tip of the guidecatheter is not supported when accessing frontal recess or ostium. Thebalance of strength and flexibility is thus particularly challenging forthe distal portion. The distal portion may also be radiopaque tofacilitate visualization under fluoroscopy.

FIG. 4A illustrates a view of a guidewire 300 according to certainembodiments of the present invention. Guidewire 300 includes core wire310 and outer coil 320. While outer coil 320 encircles at least aportion of core wire 310, for ease of illustration outer coil 320 isdepicted in cross section. Core wire 310 has proximal portion 312,transition portion 314, and distal portion 316. Proximal tip 330 anddistal end 340 are connected to outer coil 320 and core wire 310. Outercoil 320 may also be attached to core wire 310. For example, outer coil320 may be attached to core wire 310 along proximal portion 312. Markercoil 350 is connected to distal portion 316 and may also be connected todistal tip 340. Marker coil 350 may be alternatively or additionallyconnected to distal tip 340.

Still referring to FIG. 4A, proximal portion 312 of core wire 310extends from about proximal tip 330 to transition portion 314. Incertain embodiments, the length of proximal portion 312 can range fromabout 30 cm to about 100 cm. In certain embodiments, the length ofproximal portion 312 is about 78 cm. In certain embodiments, proximalportion 312 has a generally circular cross section. In otherembodiments, proximal portion 312 has a non-circular cross section. Incertain embodiments, the cross section of proximal portion 312 may begenerally symmetric such that its flexibility and rigidity are uniformabout its long axis. While proximal portion 312 may have a generallycircular cross section about substantially all of its length, thediameter of that circular cross section may vary. In certainembodiments, the diameter of the cross section of proximal portion 312ranges from about 0.050 inches (1.27 mm) to about 0.001 inches (0.0254mm). In certain embodiments, proximal portion 312 may have a region witha circular cross section having a diameter of about 0.019 inches (0.483mm). Moving distally along core wire 310 from this region, proximalportion 312 may have a region with a circular cross section having adiameter of about 0.016 inches (0.406 mm). In between these two regionsof differing diameters, proximal portion 312 may have a tapered regionwhose diameter varies from about 0.019 inches (0.483 mm) to about 0.016inches (0.406 mm). The diameter of the tapered region may vary linearlyor non-linearly along its length. In certain embodiments, proximalportion 312 has multiple regions of constant diameter cross sectionconnected by multiple tapered regions. Generally, the diameter of thecross section of proximal portion 312 decreases in the distal direction.In certain embodiments, the region of proximal portion 312 that isimmediately proximal of transition portion 314 has the smallest diametercross section of any region of proximal portion 312. In certainembodiments, this distal-most region of proximal portion 312 has a crosssection with a diameter of about 0.0065 inches (0.165 mm).

Referring still to FIG. 4A, core wire 310 includes distal portion 316.Distal portion 316 extends from about distal tip 340 to transitionportion 314. In certain embodiments, the length of distal portion 316ranges from about 0.2 cm to about 2.0 cm. In certain embodiments, thelength of distal portion 316 is about 0.5 cm. In certain embodiments,distal portion 316 has a generally circular cross section. In otherembodiments, distal portion 316 has a non-circular cross section. Incertain embodiments, the cross section of distal portion 316 may begenerally symmetric such that its flexibility and rigidity are uniformabout its long axis. The diameter of the cross section of distal portion316 may be generally constant along its length or the diameter may vary.In certain embodiments, the diameter of the cross section of distalportion 316 ranges from about 0.050 inches to about 0.001 inches. Incertain embodiments, the diameter of the cross section of distal portion316 is about 0.007 inches (0.178 mm) along substantially all of itslength.

Referring still to FIG. 4A, transition portion 314 extends from proximalportion 312 to distal portion 316. In certain embodiments, the length oftransition portion 314 ranges from about 0.5 cm to about 5.0 cm. Incertain embodiments, the length of distal portion 316 is about 0.5 cm.The transition portion, and in particular the cross section of thetransition portion, is discussed in more detail below in reference toFIGS. 5A and 5B.

Referring again to FIG. 4A, outer coil 320 is disposed around core wire310. In certain embodiments, outer coil 320 extends substantially theentire length of core wire 310. In some embodiments, outer coil 320 isshorter than core wire 310, and in other embodiments outer coil 320 islonger than core wire 310. In certain embodiments, the wire formingouter coil 320 may have a circular cross section, as shown in FIG. 4A.In other embodiments, the wire forming outer coil 320 may have anon-circular cross section, such as a rectangular cross section. Incertain embodiments, the pitch of outer coil 320 is closed, such thatthere is substantially no space between coils. In certain embodiments,the pitch of outer coil 320 is open, such that there is space betweencoils. In certain embodiments, outer coil 320 has regions of both closedand open pitch. Open pitch coils tend to be more flexible than closedpitch coils while closed pitch coils tend to have better pushabilitythan open pitch coils. It may be advantageous to vary the flexibility ofone section of outer coil 320 as compared to another section.

Still referring to FIG. 4A, depth marker 360 is a region of outer coil320 that is visually distinct from the rest of outer coil 320. Depthmarker 360 may be an etched or colored region of outer coil 320. Depthmarker 360 allows a physician to determine how much of the guidewire isinside a patient's anatomy. In certain embodiments, the length of depthmarker 360 ranges from about 3 mm to about 15 mm. In certainembodiments, the length of depth marker 360 is about 9 mm.

Referring again to FIG. 4A, proximal tip 330 is connected to outer coil320 and core wire 310. In certain embodiments, proximal tip 330 has arounded surface for ease of handling. Distal tip 340 is also connectedto outer coil 320 and core wire 310. In certain embodiments, distal tip340 has a rounded surface to provide an atraumatic tip for minimizingdamage to tissue during guidewire use.

FIG. 4B illustrates a close-up view of the distal region of guidewire300. In the embodiment illustrated in FIG. 4B, the distal region ofguidewire 300 has been pre-shaped to include a bend and further includesradiopaque marker 350. In certain embodiments, the angle of the bendranges from about 1 degree to about 135 degrees. In certain embodiments,the angle of the bend ranges from about 15 degrees to about 30 degrees.In some embodiments, the angle of the bends can be about 30 degrees,about 45 degrees, about 60 degrees, about 70 degrees, about 90 degrees,or about 120 degrees. The distal tip may be preshaped or it may beshaped by the user.

Still referring to FIG. 4B, radiopaque marker 350 is connected to distaltip 340. In certain embodiments, radiopaque marker 350 is connected todistal portion 316. In certain embodiments, radiopaque marker 350 isconnected to transition portion 314. In certain embodiments, radiopaquemarker 350 is connected to outer coil 320. Radiopaque marker 350 may bea coil, as in the embodiment depicted in FIG. 4B, or it maybe anothershape. In certain embodiments, the length of radiopaque marker 350ranges from about 0.2 cm to about 2 cm. In certain embodiments, thelength of radiopaque marker 350 is about 0.5 cm.

FIGS. 5A and 5B illustrate two views of a core wire 310 according to oneembodiment. The perspective of FIG. 5A is 90 degrees different from theperspective of FIG. 5B. In these complementary views, the shape oftransition portion 314 is more easily appreciated. FIG. 5A is a similarperspective to FIG. 4B. From FIG. 5B, it is apparent that transitionportion 314 has flattened profile. In certain embodiments, transitionportion 314 has a generally rectangular cross section. In certainembodiments, transition portion has a generally elliptical crosssection. Typically, the width of transition portion 314 (the width isthe dimension depicted in FIG. 5B, for example) is greater than thethickness of transition portion 314 (the thickness is the dimensiondepicted in FIG. 5B, for example). In certain embodiments, the width oftransition portion 314 can range from about 0.002 inches (0.051 mm) toabout 0.1 inches (2.54 mm). In certain embodiments, the width oftransition portion 314 is about 0.01 inches (0.254 mm). In certainembodiments, the thickness of transition portion 314 can range fromabout 0.001 inches (0.0254 mm) to about 0.08 inches (2.032 mm). Incertain embodiments, the thickness of transition portion 314 is about0.0035 inches (0.0889 mm).

Referring still to FIGS. 5A and 5B, the flattened cross section oftransition portion 314 provides certain advantageous mechanicalproperties. For example, transition portion 314 will bend more easily inits thickness dimension than in its width dimension. This type ofbending is depicted, for example, in FIG. 4B. In contrast, proximalportion 312 does not have a preferential bending direction, in certainembodiment of the invention where proximal portion 312 has a circular orother symmetrically shaped cross section. Generally, a wire flexes andcreates and angle with its long axis. This axis of flexion is generallyindependent of wire orientation when the wire has a symmetric crosssection. In certain embodiments where transition portion 314 has aflattened cross section, transition portion 314 is more flexible alongone axis of flexion than another. Preferential flexibility is useful ina sinuplasty guidewire, for example, to facilitate guidewire steering.

In certain embodiments, the cross sections of the different portions ofthe core wire are arranged in specific relationships in order to providethe appropriate balance of properties for use in a sinuplasty guidewire.In certain embodiments, the cross sectional area of a distal portion ofthe core wire is greater than the cross sectional area of the transitionportion of the core wire. In such embodiments, the distal portion mayhave sufficient resilience and rigidity to probe sinus cavities and bonystructures while the transition portion may be flexible and steerable.In certain embodiments, the cross sectional area of a distal portion ofthe core wire is greater than the cross sectional area of a proximalportion of the core wire. In such embodiments, the distal portion mayhave sufficient resilience and rigidity while the proximal portion maybe flexible and steerable. In certain embodiments, the diameter of thecross section of a distal portion of the core wire is greater than thethickness of the cross section of the transition portion of the corewire. In certain embodiments, the diameter of the cross section of adistal portion of the core wire is at least twice the thickness of thecross section of the transition portion of the core wire.

Guidewires of certain embodiments have different amounts of flexibilityin different regions. For example, a proximal region of guidewire(extending from the proximal end of the guidewire to a point rangingfrom about 15 cm to about 88 cm distal of the proximal end) may have astiffness ranging from about 6000 mg force (Gurley units) to about18,000 mg force. Continuing this example, a mid section of the guidewire(extending about 10 cm distally from the distal end of theaforementioned proximal section) may have a stiffness ranging from about2400 mg force to about 2800 mg force. Continuing this example, a distalsection of the guidewire (the final section of the guidewire, about 2 cmin this example) may have a stiffness ranging from about 200 mg force toabout 400 mg force. In this example, the guidewire has a balance offlexibility and rigidity.

Referring now again to FIG. 4B, and keeping in mind the flattened crosssection of certain embodiments of transition portion 314, proximalportion 312 is connected to transition portion 314 via proximaltransition taper 313. Further, transition portion 314 is connected todistal portion 316 via distal transition taper 315. The cross sectionsof proximal transition taper 313 and distal transition taper 315 may be,independently, flattened or symmetric.

Guidewires and their constituent parts for use according to embodimentsthe present invention may be manufactured as follows. Core wire 310 canbe formed by any known wire-forming process, such as drawing. Anyconventional wire material may be suitable for forming core wire 310.However, certain embodiments may use materials generally known for theiruse in medical devices, such as alloys of stainless steel and alloys ofnickel and titanium (conventionally known as nitinol or NiTi). Incertain embodiments, core wire 310 is formed from a nickel-titaniumalloy. The profile of the cross section of a region of core wire 310 maybe formed by the choice of draw plate in the drawing process, or it maybe formed by a grinding or other shaping process after the wire isdrawn. Similarly, the different diameters and the tapered regions ofcore wire 310 may be formed by further reducing the diameter of thoseregions using a staged drawing technique or by a material removaltechnique, such as grinding. Also, transition portion 314 may be formedby drawing techniques or material removal techniques. Further,transition portion 314 may be formed by a flattening, rolling, orstamping technique (or an equivalent technique). Conventional metalworking techniques, such as cold working or heat treatment, may also beused to impart useful properties to core wire 310. For example, theaustenite finish temperature of the nitinol alloy used to form the corewire may be controlled to impart a desired flexibility and resilience.

Outer coil 320 may also be formed from any conventionally known wireforming material. Certain embodiments may use materials generally knownfor their use in medical devices, such as alloys of stainless steel,alloys of nickel and titanium, platinum and the like. In certainembodiments, outer coil 320 is formed from a stainless steel alloy.Outer coil 320 may be formed from a round wire, a flat wire, or a wireof any other cross section. In certain embodiments, outer coil 320 isformed by wrapping wire around a mandrel to form a coil. The coil canthen be removed from the mandrel and placed coaxially with a core wire.Alternatively, outer coil 320 can be formed by wrapping a wire directlyaround a core wire such that the core wire acts as the mandrel forforming the coil.

Radiopaque marker 350 may be formed from any conventionally knownradiopaque materials, including iridium, platinum, tungsten, gold oralloys thereof. In certain embodiments, radiopaque marker 350 is formedfrom an alloy of 92% platinum and 8% tungsten. Radiopaque marker 350 maybe formed into a coil by wrapping around a mandrel (including using thecore wire as a mandrel). In certain embodiments, radiopaque marker 350may be placed around core wire 310. In certain embodiments, radiopaquemarker 350 is a coil with the same inner diameter and pitch as a regionof outer coil 320. In such embodiments, radiopaque coil 350 may beplaced such that the coils of outer coil 320 alternate with the coils ofradiopaque marker 350. In some embodiments, radiopaque marker 350 is nota coil, but a tab of material that can be attached to another componentof the guidewire. In certain embodiments, a region of outer coil 320 mayitself be formed of radiopaque material.

Components of the guidewire may be connected with one another by anysuitable method, including welding, soldering, brazing, swaging,adhesives, laser bonding, compression fitting, or combinations thereof.In certain embodiments, the proximal and distal ends of the guidewireare connected using solder that forms the proximal tip 330 and thedistal tip 340. In such embodiments, a plug of solder is brought intocontact with the end of the guidewire and the region is heated to causethe solder flow. The final shape of the tip can be controlled and formedinto a rounded, atraumatic shape. In other embodiments, proximal tip 330and, independently, distal tip 340 can be formed from rounded componentsthat are attached to the ends of the guidewire. These tip components canbe formed of any suitable material.

Lubricious coatings may be applied to any of the parts of guidewire 300.Such coatings are intended to reduce friction. Core wire 310 may have alubricious coating, for example, to reduce the friction between it andthe inner surface of outer coil 320. Similarly, the inner surface ofouter coil 320 may have a lubricious coating to reduce the frictionbetween it and core wire 310. The outer surface of outer coil 320 mayhave a lubricious coating to reduce the friction between it and tissue.Lubricious coatings may be formed from any suitable material, includingpolymers, such at PTFE, and hydrogels conventionally used in medicaldevices as lubricious coatings. In certain embodiments, the lubriciouscoating is formed of silicone polymer.

Guidewires made according to embodiments of the present invention can beused in sinusplasty procedures. Specifically, such guidewires can beused to locate the desired sinus anatomy and provide support for adilating member or other treatment device because such guidewiresachieve the appropriate balance of flexibility, rigidity, steerability,resilience, and support. In particular, such guidewires are usefulbecause, as compared to guidewires typically used in the vasculature,they can provide support for a dilating member with less reliance on thepatient's anatomy to assist in supporting the dilating member.

EXAMPLE

In one example, the stiffness of a guidewire designed and constructedaccording to an embodiment of the present invention was compared to astandard sinuplasty guidewire and a “floppy” sinusplasty guidewire.

An 80 cm guidewire with the following dimensions was tested in astandard guidewire flexibility test (STM02236):

Core Wire (Nickel Titanium)

-   -   1^(st) proximal region—length 55.8 cm; diameter 0.019 inches    -   1^(st) taper region—length 3.5 cm    -   2^(nd) proximal region (mid region)—length 14.5 cm; diameter        0.016 inches    -   2^(nd) taper region—length 3.2 cm    -   3^(rd) proximal region—length 1.5 cm; diameter 0.0065 inches    -   transition region—length 1.1 cm; thickness 0.0035 inches; width        0.01 inches    -   distal region—length 0.2 cm; diameter 0.007 outer coil        (stainless steel)    -   formed of 0.007 inch wire to 0.033 inch coil; length 80 cm        radiopaque coil (92% platinum/8% tungsten)    -   0.016 inch diameter coil; length 0.5 cm proximal and distal tips    -   smooth solder caps

The stiffness of 10 samples of such a guidewire was compared at thedistal region (final 3 cm) and at the balloon support region (distal 10cm). The results are presented in Table 1 below:

TABLE 1 Stiffness Comparison (mg Force) Distal region (Ave) SupportRegion (Ave) Test GW 2582.9 431.6 Standard GW 3227.4 461.1 Floppy GW1227.7 344.1

The test guidewire provides about 20% less balloon support than standardguidewire and about 50% more than the floppy guidewire. The testguidewire provides comparable distal flexibility as compared to thestandard guidewire.

While the invention has been described with reference to certainembodiments, various changes may be made and equivalents may besubstituted without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from itsscope. Therefore, it is intended that the invention not be limited tothe particular embodiment disclosed, but that the invention will includeall embodiments falling within the scope of the appended claims.

1. A core wire for a device useable in ear, nose and throat procedures,the core wire comprising: a proximal portion having a firstcross-sectional area; a distal tip having a second cross-sectional area;and a transitional portion between the proximal portion and the distaltip, the transitional portion having a third cross-sectional area,wherein the second cross-sectional area is greater than the thirdcross-sectional area.
 2. The core wire of claim 1, wherein the proximalportion of the core wire is tapered from a fourth cross-sectional at aproximal end of the wire to the first cross-sectional area at a distalend of the proximal portion.
 3. The core wire of claim 2, wherein thesecond cross-sectional area is greater than the first cross-sectionalarea.
 4. The core wire of claim 1, wherein the transitional portion hasa rectangular cross-sectional profile.
 5. The core wire of claim 1,wherein the transitional portion has an elliptical cross-sectionalprofile.
 6. The core wire of claim 1, wherein the transitional region ismore flexible along one axis of flexion than along another axis offlexion.
 7. The core wire of claim 1, wherein a total length of the corewire is approximately 80 cm, wherein a length of the transitionalportion is between approximately 1.0 cm and approximately 1.2 cm, andwherein a diameter of the distal tip is approximately twice a smallestdiameter of the transitional portion.
 8. The core wire of claim 1,wherein the distal tip further comprises an atraumatic tip.
 9. The corewire of claim 1, wherein the core wire comprises nickel titanium alloy.10. The core wire of claim 1, wherein the proximal portion comprises asupport region having a cross-sectional diameter greater than the secondcross-sectional diameter and adapted to provide support for a dilatingmember.
 11. The core wire of claim 1, wherein the core wire furtherincludes a bend located in or adjacent the transitional portion.
 12. Thecore wire of claim 1, wherein the bend has an angle of between about 15degrees and about 30 degrees.
 13. A guidewire for use in ear, nose andthroat procedures, the guidewire comprising: an elongate core wirehaving a proximal region and a distal region, the distal region of thecore wire having: a flattened portion adapted to provide preferentialflexure along at least one axis of the wire, and a tip portion distal ofthe flattened portion, wherein at least one cross-sectional dimension ofthe tip portion is greater than at least one cross-sectional dimensionof the flattened portion; an outer coil disposed around at least aportion of the elongate core wire; and an atraumatic tip coupled to thecore wire or the outer coil.
 14. The guidewire of claim 13, wherein across-sectional diameter of the tip is larger than a smallestcross-sectional diameter of the proximal portion.
 15. The guidewire ofclaim 13, wherein the core wire is formed from a nickel titanium alloy.16. The guidewire of claim 13, wherein the outer coil is formed from asteel alloy.
 17. The guidewire of claim 13, further comprising a coatingdisposed over the outer coil.
 18. The guidewire of claim 13, wherein anouter diameter of the guidewire, measured at a portion about which theouter coil is disposed, is between about 0.030″ and about 0.040″. 19.The guidewire of claim 13, wherein the atraumatic tip is formed fromsolder.
 20. The guidewire of claim 13, further comprising at least oneradiopaque coil coupled to the wire or the coil.
 21. The guidewire ofclaim 13, further comprising a coating disposed on at least a portion ofthe wire or the coil.
 22. The guidewire of claim 13, further comprisinga depth marker on the outer coil.
 23. A method of making a core wire foruse in ear, nose and throat procedures, the method comprising:fabricating an elongate wire having a proximal section and a distalsection; configuring a portion of the distal section to havepreferential flexibility along at least one axis of the portion; andconfiguring a distal tip portion having at least one cross sectionaldimension greater than at least one cross sectional dimension of thepreferentially flexible portion.
 24. The method of claim 23, wherein theconfiguration of the preferentially flexible portion is flattened. 25.The method of claim 23, wherein the core wire is fabricated from anickel titanium alloy.
 26. The method of claim 23, further comprisinggrinding at least the proximal section of the wire to form a taper. 27.A method of making a guidewire for use in ear, nose and throatprocedures, the method comprising: fabricating an elongate core wirehaving a proximal section and a distal section; configuring a portion ofthe distal section to have preferential flexibility along at least oneaxis of the portion; configuring a distal tip portion having at leastone cross sectional dimension greater than at least one cross sectionaldimension of the preferentially flexible portion; and disposing an outercoil around at least part of a length of the core wire.
 28. The methodof claim 27, wherein configuring the preferentially flexible portioncomprises flattening the wire.
 29. The method of claim 27, furthercomprising coupling an atraumatic tip with at least one of the core wireand the outer coil.